Ionic dialysance to control the dose of dialysis. One year experience

The Diascan equipment (Hospal) measures ionic dialysane which it derives the K and the Kt. If we divide the Kt obtained with Diascan between the Kt/V obtained by a simplified formula, it result a value of V for every patient. Entering this V in the Diascan software we can obtain a Kt/V (Diascan Kt/V), similar in theory to the simplified Kt/V. In the year 2002 we have controlled the delivered dialysis in our unit with the Diascan Kt/V. The aim of the present study was to study the agreement between de Diascan Kt/V and the Lowrie Kt/V. During the year 2002, 63 patients have been dialyzed in monitors with Diascan equipment. We calculated the V of each patient by dividing the Kt Diascan between the Lowrie Kt/V in the same dialysis session. The mea of the two consecutive measurements was considered the V value. Throughout the year 2002, 7 agreement studies were realized. The inter-method variability was assessed by the relative difference (absolute difference Diascan Kt/V-Lowrie Kt/V, divided by the average of both tests). A good agreement was considered when the relative difference was equal or lower than 10%. In the 7 agreement studies realized, the mean of the relative difference oscilled between 5.2 and 6.6%, and the percentage of patients with a relative difference equal or lower than 10% oscilled between 83 and 91%. During a month, the Diascan Kt/V was controlled in all dialysis sessions in 41 patients (554 sessions in total). Failure in the lecture of Kt/V Diascan was observed in 41 sessions (7%). A Diascan Kt/V greater than 1 (the minimum delivered dialysis considered in our unit) was obtained in 93% of the valid sessions. 38 of 41 patients had a mean monthly Diascan Kt/V greater than 1. The coefficient of variability of any patient oscilled between 2.1 and 12.4% (mean 5.1%). Diascan Kt/V is good procedure for the monitoring the delivered dialysis without blood sampling or any additional costs.     

Conventional blood sampling versus On-Line Clearance Monitoring

On-line Clearance Monitoring (OCM) calculates the Kt/V during a dialysis session using a module incorporated into the Fresenius 4008 H/S haemodialysis machine (1). The method is based on repeated increments in dialysate sodium concentrations followed by measuring the change of dialysate sodium concentration after the dialysate has passed through the kidney. OCM is a patient friendly, non-invasive and easy method for measuring Kt/V. Kt/V calculated on single-pool urea kinetics according to Daugirdas was compared to Kt/V measured by OCM in thirty stable patients on chronic haemodialysis. Patients were dialysed using a dialyser with either a high-flux polysulfone or a haemophane membrane. In four patients OCM was measured in ten consecutive sessions to assess the intra-individual variation in OCM. The calculated Kt/V was compared to Kt/Vocm in three patients at five consecutive dialysis sessions to measure the intra-individual correlation. A linear correlation was present between Kt/Vocal and Kt/Vac for both the polysulfone and haemophane membrane. Intra-individual Kt/Vocm showed very stable values with an average variation of less than 5%. Intra-individual correlation between calculated Kt/V and Kt/Vocm was high.     

Determination of the dose of dialysis with integrated modules in the same monitor

The "gold standard" method to measure the mass balance achieved during dialysis for a given solute is based on the total dialysate collection. This procedure is unfeasible and too cumbersome. For this reason, alternative methods have been proposed including the urea kinetic modelling (Kt/V), the measurement of effective ionic dialysance (Diascan), and the continuous spent sampling of dialysate (Quantiscan). The aim of this study was to compare the reliability and agreement of these two methods with the formulas proposed by the urea kinetic modelling for measuring the dialysis dose and others haemodialysis parameters. We studied 20 stable patients (16 men/4 women) dialyzed with a monitor equipped with the modules Diascan (DC) and Quantiscan (QC) (Integra. Hospal). The urea distribution volume (VD) was determined using anthropometric data (Watson equation) and QC data. Kt/V value was calculated according to Daurgidas 2nd generation formula corrected for the rebound (eKt/V), and using DC (Kt/VDC) and QC (Kt/VQC) data. The total mass of urea removed was calculated as 37,93 +/- 16 g/session. The VD calculated using Watson equation was 35.7 +/- 6.6 and the VDQC was 35.06 +/- 9.9. And they showed an significative correlation (r:0,82 p < 0.001). The (VDQC-VDWatson) difference was -0.64 +/- 5.8L (ns). Kt/VDC was equivalent to those of eKt/V (1.64 +/- 0.33 and 1.61 +/- 0.26, mean difference -0.02 +/- 0.29). However, Kt/VQC value was higher than eKt/V (1.67 +/- 0.22 and 1.61 +/- 0.26 mean difference 0.06 +/- 0.07 p < 0.01). Both values correlated highly (R2: 0.92 p < 0.001). Urea generation (C) calculated using UCM was 8.75 +/- 3.4 g/24 h and those calculated using QC was 8.64 +/- 3.21 g/24 h. Mean difference 0.10 +/- 1.14 (ns). G calculated by UCM correlated highly with that derived from QC (R2: 0.88 p < 0.001). In conclusion, Kt/VDC and Kt/VQC should be considered as valid measures for dialysis efficiency. However, the limits of agreement between Kt/VQC and eKt/V were closer than Kt/VDC.     

Monitoring hemodialysis dose with ionic dialisance in on-line hemodiafiltration

Until now, with the ionic dialysance measurement, it has been possible to determine hemodialysis dose in each session of hemodialysis (HD) and in the conventional hemofiltration (HDF) but not in the modality of on-line HDF. Recently it is possible with a new biosensor that allows to measure the dose in on-line HDF. The aim of this study was to evaluate the value of this biosensor in different dialysis situations comparing the dialysis dose measured in blood in comparison with the values obtained from the sensor. We have analysed 192 hemodialysis sessions performed in 24 patients, 15 male and 9 female, mean age of 70.2 +/- 12 years, included in on-line HDF. All treatments were done using 4008H (Fresenius) monitor equipped with on-line clearance monitoring (OCM), that measure, with non invasive monitoring, the effective ionic dialysance equivalent to urea clearance. Every patient received eight dialysis sessions: one with dialysate flow (Qd) 500 ml/min, two with HD and Qd 800 ml/min and five with on-line HDF. Other habitual haemodialysis parameters were no changed, dialysis time 200 +/- 63 min (135-300) and blood flow 421 +/- 29 ml/min (350-450). Initial and final ionic dialysance values (K), final Kt, Kt/V measured with OCM using V of Watson, and Kt/V determined in blood pre and postdialysis concentrations of urea (Daugirdas second generation), were measured. The mean of initial K was 251 +/- 21 ml/min and the final K was 234 +/- 24 ml/min. The Kt measured with OCM was 50.6 +/- 17 L, 51.2 +/- 17 in men and 49.7 +/- 16 in women. The V (Watson) was 34.5 +/- 6 L. The Kt/V measured with the Kt of OCM and V was 1,499 +/- 0.54 and Kt/V measured in blood samples was 1,742 +/- 0.58. The correlation between both values was 0.956. The Kt was different according to dialysis modality used: in HD and Qd 500 was 44.7 +/- 15 L, in HD and Qd 800 was 50.7 +/- 17 and in on-line HDF (22.1 +/- 7 L of reposition volume), was 51.8 +/- 17 L. The Kt/V from blood samples also shows variation: in HD and QD 500 was 1.60 +/- 0.55, in HD and Qd 800 was 1,726 +/- 0.56 and in on-line HDF was 1,776 +/- 0.59. In this study has been observed a close correlation between the new biosensor OCM with the measures obtained from the blood samples. For this reason this sensor it is useful in all modalities of dialysis treatment, included on-line HDF. The sensor was able to discriminate the efficacy of different dialysis modalities used in this study.     

Kt as control and follow-up of the dose at a hemodialysis unit

To ensure our patients are receiving an adequate dose in every dialysis session there must be a target to achieve this in the short or medium term. The incorporation during the last years of the ionic dialysance (ID) in the monitors, has provided monitoring of the dialysis dose in real time and in every dialysis session. Lowrie y cols., recommend monitoring the dose with Kt, recommending at least 40 L in women and 45 L in men or individualizing the dose according to the body surface area. The target of this study was to monitor the dose with Kt in every dialysis session for 3 months, and to compare it with the monthly blood test. 51 patients (58% of our hemodialysis unit), 32 men and 19 women, 60.7+/-14 years old, in the hemodialysis programme for 37.7+/-52 months, were dialysed with a monitor with IC. The etiology of their chronic renal failure was: 3 tubulo-interstitial nephropathy, 9 glomerulonephritis, 12 vascular disease, 7 polycystic kidney disease, 7 diabetic nephropathy and 13 unknown. 1,606 sessions were analysed during a 3 month period. Every patient was treated with the usual parameters of dialysis with 2.1 m2 cellulose diacetate (33.3%), 1.9 m2 polisulfone (33.3%) or 1.8 m2 helixone, dialysis time of 263+/-32 minutes, blood flow of 405+/-66, with dialysate flow of 712+/-138 and body weight of 66.7+/-14 kg. Initial ID, final ID and Kt were measured in each session. URR and Kt/V were obtained by means of a monthly blood test. The initial ID was 232+/-41 ml/min, the final ID was 197+/-44 ml/min, the mean of Kt determinations was 56.6+/-14 L, the mean of Kt/V was 1.98+/-0.5 and the mean of URR was 79.2+/-7%. Although all patients were treated with a minimum recommended dose of Kt/V and URR when we used the Kt according to gender, we observed that 31% of patients do not get the minimum dose prescribed (48.1+/-2.4 L), 34.4% of the men and 26.3% of the women. If we use the Kt individualized for the body surface area, we observe that 43.1% of the patients do not get the minimum dose prescribed with 4.6+/-3.4 L less than the dose prescribed. We conclude that the monitoring of dialysis dose with the Kt provides a better discrimination detecting that between 30 and 40% of the patients perhaps do not get an adequate dose for their gender or body surface area.     

Mathematical analysis of urea rebound in long-term hemodialysis patients

Quantifying hemodialysis (HD) treatment requires knowledge of the equilibrated concentrations of the post-HD small molecule rebounds. However, measurement of the equilibrated concentrations is only possible after resting in bed after HD for at least 30 min, and this is often impractical. Therefore, we have analyzed mathematically the time course of post-HD urea rebound, and from this, have derived a new formula for predicting its equilibrated concentration. The blood urea nitrogen (BUN) was measured at 10 time points (immediately following HD, and 0.5, 2.5, 5, 7.5, 10, 15, 20, 25, and 30 min post-HD) in 12 anuric HD patients. The absolute change in the urea rebound (DeltaeqBUN) was approximated (DeltaestBUN) using the equation: DeltaestBUN = b -[1-exp x (-c x time (min))] + a x time (min). After the good correlation between DeltaeqBUN and DeltaestBUN, we compared the value of DeltaeqBUN measured at 30 min (DeltaeqBUN(30)) with that calculated (DeltaestBUN(30)) using only four sample points (immediately following HD, and 2.5, 5 and 10 min post-HD). Based on this result, we tried to predict post-HD BUN at 30 min (estBUN(30)). This study was undertaken to determine whether estBUN(30) may be representative of the equilibrated BUN (eqBUN(30)), and to compare with Kt/V using estBUN(30) and eqBUN(30). There was a significant correlation between DeltaeqBUN and DeltaestBUN (0.97 < r < 0.99, P < 0.001). Thus, there was a significant positive linear correlation between eqBUN(30) and estBUN(30) (eqBUN(30): 25.7 +/- 2.25 mg/dL, estBUN(30): 26.3 +/- 2.31 mg/dL; r(2) = 0.99, P < 0.001). A Kt/V measurement was obtained with single pool model using BUN just after HD (Kt/V(sp)), eqBUN(30) (Kt/V(eq)), and estBUN(30) (Kt/V(est)), and with double pool model using Kt/V(sp) (Kt/V(dp)) and was compared with them. Though Kt/V(sp) was significantly higher than Kt/V(eq) (1.26 +/- 0.08 vs. 1.09 +/- 0.07, P < 0.001), there were no differences among Kt/V(eq), Kt/V(est) and Kt/V(dp) (Kt/V(est): 1.06 +/- 0.07, Kt/V(dp): 1.10 +/- 0.07) and all values were clinically acceptable. Furthermore, there was a significant positive linear correlation between Kt/V(eq) and Kt/V(est) (r(2) = 0.98, P < 0.001). In conclusion, we have devised the method to predict equilibrated BUN and calculate double pool Kt/V, which requires samples up to 10 min post-HD.     

Influence of post haemodialysis sampling on Kt/V result

The recommended Kt/V is 1.2. Unfortunately there is no written policy for nurses on the procedure for taking blood urea nitrogen samples post haemodialysis. The aim of this study was to establish the Kt/V variability of haemodialysis patients depending on the method of collection of post-haemodialysis blood urea nitrogen. Twenty-two patients were analysed. A Kt/V was performed every 15 days during a period of 2 months. It was taken five times on each patient: 30 minutes before the end of a haemodialysis session (Kt/V30), at the end of haemodialysis (Kt/V1), after slowing flows (50 ml/min) for 2 minutes (Kt/V2) and after the blood circuit had been returned to the patient at 5 and 15 minutes respectively. (Kt/V5, Kt/V15). The Kt/V results were: Kt/V1 1.23 +/- 0.2 Vs Kt/V2 1.14 +/- 0.19 (p < 0.003); Kt/V5- 1.05 +/- 0.19 (p < 0.002 Vs Kt/V2); Kt/V15 1 +/- 0.16 (p < 0.05 Vs Kt/V5); Kt/V30 1.12 +/- 0.21 (pNS Vs Kt/V2). In conclusion, there was a large variability in the Kt/V depending on the method of collection of the blood urea nitrogen sample post-haemodialysis.     

Correlates of urea kinetic modeling during hemodialysis in patients with acute renal failure

The current guidelines on dialysis adequacy in acute renal failure (ARF) are loosely defined and have been extrapolated from patients with end-stage renal disease. The objectives of this study were (1) to compare three methods of urea kinetic modeling measurement in patients with ARF receiving intermittent hemodialysis, (2) to compare prescribed to delivered dose of dialysis, and (3) to explore the factors that are associated with dialysis delivery. 'Single-pool' urea kinetic modeling was assessed by the Ureakin) software and the second-generation equation which uses a logarithmic estimate of spKt/V. 'Equilibrated' Kt/V (eKt/V) was calculated using the rate adjustment equation. The prescribed dose was derived using the manufacturer's specifications of the dialyzer clearance, prescribed time, actual delivered blood and dialysate flow, and estimates of volume of urea distribution. A total of 78 consecutive spKt/V measurements were obtained in 24 patients. The mean urea reduction ratio was 51 +/- 1%. The delivered spKt/V was significantly lower than that prescribed (0.87 +/- 0.03 or 0.83 +/- 0.03 vs. 1.28 +/- 0.05; p = 0.0001). The equilibrated Kt/V was markedly lower than the delivered spKt/V (0.73 +/- 0.03 vs. 0.83 +/- 0.03; p = 0.0001). Univariate analyses demonstrated that female gender, low body mass index, low predialysis weight, use of cellulose acetate dialyzers, and increased prescribed time were associated with increased odds of prescribed spKt/V > or =1.2. Similarly, old age, increased delivered time, and high cytokine production were associated with increased odds of delivered spKt/V > or =1.2. In summary, while the impact of delivered intermittent hemodialysis on the survival of patients with ARF remains to be determined, these results indicate that dialysis delivery is suboptimal in ARF, and empiric dosing should strongly consider factors related to lean body mass, including age and gender.     

Characteristics of patients on hemodialysis therapy for more than 30 years

Since its experimental introduction in 1960, hemodialysis has become a widely performed and relatively safe procedure. Therapeutic strategies have been developed, and the numbers of long-term survivors of hemodialysis therapy have been increasing. Hemodialysis therapy was introduced at Sangenjaya Hospital in October 1970, and the 16 patients who have survived for more than 30 years on hemodialysis therapy since its introduction at the hospital were enrolled in this study to investigate the characteristics of long-term hemodialysis patients. For comparison, 50 patients on hemodialysis for less than 30 years were also studied (21 patients with <10 years hemodialysis, 13 with 10-20 years hemodialysis and 16 with 20-30 years hemodialysis). Background information (age, gender, and cause of renal disease), dialysis dose (single pool [sp.] Kt/V), mineral metabolism (serum phosphate), anemia management (serum hemoglobin), and nutrition (serum albumin and reduced interdialytic weight gain) were assessed. Hemodialysis was instituted at 28.7 +/- 6.4 years of age. The primary cause of end-stage renal disease was chronic glomerulonephritis in all of the patients except one, and in that patient it was polycystic kidney disease. As an index of the dialysis dose, sp. Kt/V was 1.2 +/- 0.11. As an index of mineral metabolism, serum phosphate was 5.4 +/- 0.9 mg/dL. As an index of anemia management, serum hemoglobin was 10.2 +/- 1.2 g/dL. As indexes of nutrition, serum albumin was 4.0 +/- 0.2 g/dL and interdialytic weight gain was 4.43 +/- 1.36%. The sp. Kt/V-value, serum phosphate, serum hemoglobin and interdialytic weight gain did not differ between the four different hemodialysis duration groups. Serum albumin was lower in the >30 group (4.0 +/- 0.2 g/dL) than in the <10 group (4.2 +/- 0.3 g/dL) (P = 0.046). As the duration of hemodialysis has increased, the age at hemodialysis induction has become younger. The cause of the renal failure was chronic glomerulonephritis in most of the cases. None had diabetic nephropathy. Improvement of the prognosis of patients with diabetic nephropathy is required. Most of the indexes of these patients nearly satisfied the recommended values.     

The circadian blood pressure rhythm in non-diabetic hemodialysis patients.

This study investigates the circadian blood pressure variation of non-diabetic chronic hemodialysis (HD) patients on both HD and non-HD days as well as the factors affecting diurnal BP variation. Forty-nine HD patients aged 61.8 +/- 12.9 years who were on daytime HD for 97 +/- 68 months were studied. No significant difference was found in every daytime and nighttime BP between the first (HD) and the second (non-HD) day. However, the ratio nighttime/daytime BP was significantly higher on the second day. Each BP diurnal variability pattern was classified as either Dipper (D: the ratio nighttime/daytime mean BP 0.8-0.9), non-dipper (0.9 < ND < 1.0), or inverted dipper (ID > 1.0). More than 75% of the cases were classified as ND (26 cases) or ID (11 cases). The ultrafiltration rate in D was significantly less than that in ND and ID. The difference of plasma renin activity between pre- and post-HD (dRen) was significantly higher in ID than in D and ND. The amount of dialysis (Kt/V) was found to be significantly correlated with nighttime BP fall. Ultrafiltration, dRen and Kt/V were independent factors for the abnormal BP diurnal variability. In conclusion, the decreased nocturnal BP fall seen in non-diabetic HD patients is associated with increased extracellular fluid even in the patients without overt overhydration, whereas relatively insufficient amount of dialysis (low Kt/V) may be another possible cause. The increased dRen observed only in ID patients may reflect occult cardiovascular damage or functional disturbances in aortic and carotid baroreflexes caused by arterial structural changes.     

Evaluation of pre- and postdilutional on-line hemodiafiltration adequacy by partial dialysate quantification and on-line urea monitor.

On-line highflux hemodiafiltration (HDF) is a clinically interesting and effective mode of renal replacement therapy, which offers the possibility to obtain an increased removal of both small and large solutes. The fundamental role of urea kinetic monitoring to assess dialysis adequacy in conventional hemodialysis has been widely studied. Both direct measurement of the urea removed by the modified direct dialysate quantitation (mDDQ) based on partial dialysate collection (PDC) and dialysate-based urea kinetic modeling (DUKM) using urea monitor have been advocated. The validity of this assessment tool in the patients with on-line HDF remained unclear. The aims of this investigation were (1) to compare the delivered Kt/V, urea mass removal (UMR), solute removal index (SRI) and normalized protein catabolic rate (nPCR) between pre- and postdilutional high-flux HDF; (2) to verify and compare the efficiency of pre- and postdilutional HDF using DUKM with on-line dialysate urea sensor, and mDDQ with partial dialysate collection. During both mode of HDF, the paired analysis urea removed and Kt/V showed no significant difference. Using mDDQ, mean values for predilutional mode were as follows: Kt/V 1.53 +/- 0.01 UMR, 16.8 +/- 0.3 g/session; urea clearance 178 +/- 18 ml/min; SRI 75.5 +/- 7.7%; urea distribution volume (V) 28.3 +/- 1.2 liters; nPCR 1.34 +/- 0.18 g/kg/day; on the other hand, mean values for postdilutional mode were Kt/V 1.58 +/- 0.01; UMR 17.10 +/- 0.28 g/session; urea clearance 184 +/- 21 ml/min; SRI 77.2 +/- 3.5%; urea distribution volume, 27.8 +/- 1.5 liters; nPCR 1.34 +/- 0.19 g/kg/day. The mean value of urea generation rate was 5.82 +/- 1.12 mg/min during HDF. Our results showed that dialysis adequacy was achieved with both high-volume predilutional HDF and postdilutional HDF. These two modes of HDF provided similar and adequate small solute clearance. In addition, we found that on-line analysis of urea kinetics is a reliable tool for quantifying and assuring delivery of adequate dialysis.     

Acetate-free hemodialysis: a feasibility study on a technical alternative to bicarbonate dialysis

This study aimed at evaluating the feasibility of an acetate-free hemodialysis (AFHD) technique, comparing it with acetate-free biofiltration (AFB) and bicarbonate dialysis (BD). The assessment of the parameters concerned: electrolyte kinetics (Na+, K+), acid-base balance (HCO3-, pH), dialysis efficiency (Kt/V), serum beta2-microglobulin reduction ratio, nutritional status (normalized protein catabolic rate, serum albumin and total proteins, body mass index), hemopoietic status (hemoglobin, hematocrit), and some clinical parameters (systolic and diastolic blood pressures, heart rate, percent blood volume reduction measured by Hemoscan). Nine patients participated in this study which was conducted using a Latin square randomized experimental design. The results of the last week of each month of the study (1 month for each technique) were analyzed by means of Anova for repeated measures. The different treatments were comparable with regard to the main dialysis parameters such as blood flow (320 ml/min) and weight loss rate (0.6 +/- 0.1 kg/h), while dialysis length and dialysate conductivities were different, depending on the dialysis technique. Electrolyte kinetics and acid-base balance were similar during the three periods. The dialysis efficiency for small molecules (Kt/V of urea) was similar (between 1.4 and 1.6); however, AFB seemed to show a higher beta2-microglobulin reduction rate (47.6 +/- 4 vs. 4.3 +/- 10% for AFHD and vs. 9.9 +/- 5% for BD; p < 0.001). The nutritional and hemopoietic status maintained stable, and the hemodynamic parameters were comparable during all periods. The percent blood volume reduction at the end of the treatments was not statistically different (-14.9 +/- 9.4% in AFB, -12.1 +/- 5.1% in AFHD, and -12.2 +/- 4.4% in BD), and these results could explain the similar hemodynamic behavior during the three periods. In conclusion, AFHD appears to be a safe technique which has all positive effects of AFB and the low costs of BD. In our opinion, it could be used in patients with few clinical impairments, usually treated with hemodialysis, in whom a biocompatible treatment is indicated.     

Temporary hemodialysis catheters as a long-term vascular access in chronic hemodialysis patients

The objective was to review our experience with temporary, precurved, jugular catheters used for long-term vascular access in chronic hemodialysis patients. Thirty chronic hemodialysis patients, 14 men and 16 women, with an average age of 65.3 +/- 13.5 years (30-90 years), treated by dialysis for 1 month to 30 years (average +/- SD, 6.3 +/- 8.1 years), had single lumen, 'temporary' precurved non-tunneled jugular catheters placed into the right jugular vein as permanent vascular access, with 4% trisodium citrate as a locking solution and mupirocin at the exit site. Hemodialysis catheters were used for vascular access on average for 9.1 +/- 6.5 months, (1-22.7 months), and for a total of 271.7 months (8151 days). Average catheter functioning time was 3.1 +/- 1.9 months (0.5-10 months). The total number of side-effects was 55 (6.7/1000 catheter days), including 26 cases of thrombosis (3.2/1000 catheter days), 9 ruptures of the catheter (1.1/1000 catheter days), 15 catheter malfunctions (1.8/1000 catheter days), 2 exit site infections (0.2/1000 catheter days), 2 bacteremias (0.2/1000 catheter days), 1 avulsion of the catheter (0.1/1000 catheter days), and 2 catheters were removed because an AV fistula was successfully used. In 21 patients single-needle hemodialysis was performed, mean blood flow 251 +/- 16 mL/min (250-300), mean Kt/V 0.96 +/- 0.16 (0.72-1.27) and in 9 patients double-needle hemodialysis was performed (catheter and peripheral vein) with mean blood flow 252 +/- 14 mL/min (200-300), mean Kt/V 1.63 +/- 0.25 (1.21-1.96). 'Temporary' jugular single lumen non-tunneled hemodialysis catheters, with 4% citrate as locking solution and mupirocin ointment at the exit site provided good long-term vascular access with acceptable functioning time and low infection rate. The main reasons for catheter exchange or removal were malfunction and mechanical damage of the catheter.     

Evaluation of methods to calculate dialysis dose in daily hemodialysis

Daily dialysis has shown excellent clinical results because a higher frequency of dialysis is more physiological. Different methods have been described to calculate dialysis dose which take into consideration change in frequency. The aim of this study was to calculate all dialysis dose possibilities and evaluate the better and practical options. Eight patients, 6 males and 2 females, on standard 4 to 5 hours thrice weekly on-line hemodiafiltration (S-OL-HDF) were switched to daily on-line hemodiafiltration (D-OL-HDF) 2 to 2.5 hours six times per week. Dialysis parameters were identical during both periods and only frequency and dialysis time of each session were changed. Time average concentration (TAC), time average deviation (TAD), normalized protein catabolic rate (nPCR), Kt/V, equilibrated Kt/V (eKt/V), equivalent renal urea clearance (EKR), standard Kt/V (stdKt/V), urea reduction ratio (URR), hemodialysis product and time off dialysis were measured. Daily on-line hemodiafiltration was well accepted and tolerated. Patients maintained the same TAC although TAD decreased from 9.7 +/- 2 in baseline to a 6.2 +/- 2 mg/dl after six months, p < 0.01. No significant changes were observed in weekly Kt/V and eKt/V throughout the study. However EKR, stdKt/V and weekly URR were increased during D-OL-HDF in 24-34%, 46% and 50%, respectively. Hemodialysis product was raised in a 95% and time off dialysis was reduced to half. CONCLUSION: Dialysis frequency is an important urea kinetic parameter which there are to take in consideration. It's necessary to use EKR, stdKt/V or weekly URR to calculate dialysis dose for an adequate comparison between different frequency dialysis schedules.     

Assessment of Dialysis Dose in Critically Ill Maintenance Dialysis Patients

Maintenance dialysis patients are admitted more frequently to the intensive care unit (ICU) and have higher ICU mortality than the general population. It is unclear if such dialysis patients receive adequate dialysis in the ICU setting. Using the Daugirdas formula for calculation of spKt/Vurea, single treatment delivered dialysis dose was assessed in 85 critically ill maintenance hemodialysis patients during their first ICU dialysis session. Weekly delivered spKt/Vurea was determined in the surviving 64 patients and compared with their corresponding delivered outpatient dialysis dosages. Outcome measures were ICU and in‐hospital mortality and mortality at 6 and 12 months after discharge. Prescribed dose of the first ICU dialysis was a spKt/Vurea of 1.43 ± 0.11, the single treatment delivered dose was 1.02 ± 0.14. The weekly prescribed ICU Kt/Vurea was 4.25 ± 0.12 and delivered ICU Kt/Vurea was 3.48 ± 0.19. Patients with sepsis had the lowest mean spKt/Vurea values (0.87 ± 0.12). Serial measurements of delivered dialysis dose suggest that this gap is explained by variability of volume of urea distribution. ICU mortality was 25% and was related to APACHE II score, but not to delivered intermittent hemodialysis dose. Critically ill maintenance dialysis patients receive suboptimal dialysis doses. The impact of short‐term underdialysis on survival of hospitalized maintenance dialysis patients remains unknown. Assessment of dialysis adequacy should be routinely performed in these patients and delivered dialysis should be tracked through the initial clinical course.     

Comparison of some nutritional parameters in hemodialysis patients over and below 65 years of age

There is a close relationship between inflammation, malnutrition and atherosclerosis in chronic hemodialysis (HD) patients (pts). This process is closely related to poor clinical outcomes including morbidity and mortality, especially in elderly patients. The aim of this study conducted in HD pts over 65 years old (group A) and in younger pts (group B) was the assessment of some parameters of: nutritional status, inflammation, atherosclerosis and anthropometry. In group A (40 pts), mean age 72,2 +/- 4,7, the time on HD treatment was 37,1 +/- 33,0 months and in group B (83 pts), mean age 48,3 +/- 9,7 years, time on HD treatment was 97,4 +/- 90,1 months. We have measured the serum concentrations (conc.) of some parameters: hemoglobin (Hb), C-reactive protein total (CRP), albumin (alb), cholesterol (t-chol), calcium (Ca), phoshorus (P), intact parathormone (iPTH). The adequacy of HD was measured by Kt/V. We have estimated: body mass index (BMI), interdialytic weight gain (IWG), normalized protein catabolic rate (nPCR) and weekly EPO consumption. Some anthropometric parameters which were studied included: triceps skin fold (TSF), waist circumference (WC), mid-arm muscle circumference (MC). The physical activity was expressed by hand grip test (GT) on the hand without the vascular access. The mean values of Kt/V were similar in both groups (1,2 +/- 0,1 vs 1,2 +/- 0,2). Likewise there were no significant differences in mean levels of CRP (9,7 +/- 9,1 vs 14,1 +/- 12,2 mg/l) and Hb (6,7 +/- 0,7 vs 7,0 +/- 0,9 mmol/l), but weekly EPO consumption was higher in group A (48,1 +/- 35,8 vs 38,6 +/- 29,3 U/kg, p<0,01). We have observed, that in group A the mean serum levels of albumin and t-chol were significantly lower (33,2 +/- 3,1 vs 37,5 +/- 3,9 g/l, p <0,05 and respectively 3,9 +/- 0,7 vs 4,3 +/- 0,9 mmol/l, p<0,05).) and IWG as well (2,1 +/- 1,2 vs 3,3 +/- 1,6 kg; p<0,01). The mean values BMI and nPCR were significantly lower in group A (24,4 +/- 3,2 vs 27,3 +/- 2,5 kg/m2, p<0,01 and respectively: 0,9 +/- 0,1 vs 1,1 +/- 0,2 g/kg/day, p<0,01). Likewise mean values of IWG and MAP were significantly lower in elderly patients (2,1 +/- 1,2 vs 3,3 +/- 1,6 kg; p<0,01 and respectively 91,5 +/- 19 vs 95,5 +/- 13 mm Hg; p<0,01). Mean serum Ca and P conc. were significantly lower in group A (2,1 +/- 0,1 vs 2,3 +/- 0,2 mmol/l, p<0,01 and respectively 1,4 +/- 0,3 vs 1,8 +/- 0,5 mmol/l, p<0,01). Likewise mean iPTH conc. was significantly lower in elderly patients (379,2 +/- 362,3 vs 571,6 +/- 510,9 pg/ml). The mean values of strength of grip were lower in group A (20,5 +/- 11,4 vs 34,7 +/- 13,6 kg, p<0,01). In both groups there were no significant differences between the mean values of TSF (11,2 +/- 3,8 vs 13,4 +/- 6,8 mm), but mean values of WC and as well MC as well were lower in group A (91,0 +/- 8,1 vs 98 +/- 12,4 cm; p<0,05 and respectively 25,5 +/- 3,1 vs 28,9 +/- 3,8 cm; p<0,05). There was a significant negative correlation (cor.) between the age of patient and intradialytic body weight gain (r = -0,4607, p<0,001) and significant positive cor. between: albumin and nPCR (r = 0,433, p<0,01) and albumin and Hb (r = 0,391, p<0,01). There was a significant negative cor. between strength of grip and time of HD treatment (r = -0,350, p<0,05). In conclusion: The studied elderly hemodialysis patients are more malnourished than younger ones.     

Short-term blood pressure, noradrenergic, and vascular effects of nocturnal home hemodialysis

Long-term nocturnal hemodialysis, which uses longer and more frequent sessions than conventional hemodialysis, lowers clinic blood pressure and left ventricular mass. We tested the hypotheses that short-term nocturnal hemodialysis would (1) reduce ambulatory blood pressure; (2) cause peripheral vasodilation; (3) lower plasma norepinephrine concentration; and (4) improve the arterial response to reactive hyperemia (a marker of endothelium-dependent vasodilation). We studied 18 consecutive patients (age, 41+/-2; [mean+/-SEM]) before and 1 and 2 months after conversion from conventional (three 4-hour sessions per week) to nocturnal (six 8-hour sessions per week) hemodialysis. As the dialysis dose per session (Kt/V) increased from 1.24+/-0.06 to 2.04+/-0.08 after 2 months (P=0.02), symptomatic hypotension developed and most antihypertensive medications were withdrawn. Nocturnal hemodialysis nonetheless lowered 24-hour mean arterial pressure (from 102+/-3 to 90+/-2 mm Hg after 2 months; P=0.01), total peripheral resistance (from 1967+/-235 to 1499+/-191 dyne x s x cm(-5); P<0.01) and plasma norepinephrine (from 2.66+/-0.4 to 1.96+/-0.2 nmol; P=0.04). Endothelium-dependent vasodilation could not be elicited during conventional hemodialysis (-2.7+/-1.8%) but was restored (+8.0+/-1.0%; P=0.001) after 2 months of nocturnal hemodialysis. The brachial artery response to nitroglycerin also improved (from 6.9+/-2.8 to 15.7+/-1.6%; P<0.05). Nocturnal hemodialysis had no effect on weight or on stroke volume. Rapid reversal of these markers of adverse cardiovascular events with more intense hemodialysis may translate into improved outcome in this high-risk group of patients.     

血液透析患者透析充分性的监测

目的　评价血液透析充分性的临床标准和尿素动力学模型 (UKM )参数 ,并观察透析后尿素反跳 (PDUR)对评价的影响。方法　按临床标准分为透析充分组 (Ⅰ组 )和透析不充分组 (Ⅱ组 ) ,分别计算PDUR以及反跳前后UKM参数即尿素清除指数 (Kt/V)、尿素时间平均浓度(TACurea)、蛋白分解率 (PCR)。结果　两组PDUR、尿量以及反跳前后的UKM参数存在显著性差异(P <0 .0 1) ;G S图显示Ⅱ组临床和参数判断基本一致 ,但Ⅰ组存在较大差异 ;平均PDUR为 17.8% ,反跳后的Kt/V、PCR值较反跳前分别下降 18.7%和 12 .7% ,而TACurea值增加 3 .1% ,PDUR与透析间尿量呈负相关 (r=-0 .64 )。结论　透析充分性评价是一连续非短期过程 ,宜综合临床和参数指标判断 ,以后者为主 ;忽视PDUR将高估透析充分性 ,宜用透析后尿素平衡浓度计算参数 ;透析不充分和残存肾功能可能影响PDUR程度。     

Assessment of salt intake in hemodialysis

One of the main goals of dialysis is to reach a correct sodium balance. Dietary sodium restriction facilitates control of thirst, water overload, hypertension and cardiac failure. Nowadays, it is possible to estimate sodium mass transfer and known interdialytic salt intake, by means of non-invasive methods. The use of dialysate sodium profiles improves dialysis tolerance but it has been reported that interdialytic thirst may increase because of an inappropriate sodium balance. The aim of this study was to evaluate the usual salt intake in hemodialysis patients, the effects on interdialytic gain weight, arterial pressure, blood volume preservation and dialysis tolerance of two different profiles of dialysate sodium and an additional session with salt restriction. Seventeen dialysis patients, 12 male and 5 females, were studied. Each patient underwent seven hemodialysis treatments: three consecutives sessions (a week) with constant sodium and ultrafiltration hemodialysis; three consecutive sessions with exponential decrease of conductivity (Initial 15.5-16.0, mid-session 14.3 and at the end 13.9-14 mS/cm) and ultrafiltration (1.6 l/h initial and 0.1 at the end) profiled hemodialysis; and an additional session which had a special dietary salt restriction. Dialysis parameters and dry weight were kept constant. Integra monitor with Diascan and Hemoscan biosensors (Hospal) were used in all sessions. We measured pre- and postdialytic plasma conductivity, sodium mass transfer, interdialytic weight gain, mean arterial pressure (MAP), percent reductions of blood volume (%R-BV) and hypotensive episodes during dialysis. Mean sodium mass transfer was 1,144 +/- 356 mmol (no profile week) vs 1,242 +/- 349 mmol (week with profiles), NS. It was equivalent to a salt ingestion of 9.6 +/- 3 and 10.4 +/- 3 g/day respectively. End plasma conductivity was 14.04 +/- 0.14 (no profile) versus 14.21 +/- 0.08 mS/cm (profiled), p < 0.001. Interdialytic weight gain was 2.49 +/- 0.76 (no profile) vs 2.32 +/- 0.56 kg (profiled), NS. MAP was 101 +/- 11 (no profile) vs 99 +/- 10 mmHg (profiled), NS. The %R-BV was -7.73 +/- 3 (no profile) vs -6.46 +/- 3% (profiled), p < 0.01. Hypotensive episodes/session were 0.66 +/- 0.75 (no profiles) vs 0.41 +/- 0.57 (profiled), NS. Mean sodium mass transfer was 356 +/- 125 mmol with usual salt intake and 240 +/- 81 mmol with salt restriction, p < 0.001. It was equivalent to a salt ingestion of 10.47 +/- 3 versus 7.06 +/- 2 g per day respectively, p < 0.001. Initial plasma conductivity was 14.31 +/- 0.21 (usually sodium intake) versus 14.16 +/- 0.17 mS/cm (salt restriction), p < 0.01. Predialysis blood pressures were decreased with dietary salt restriction, MAP was 99.1 +/- 11 vs 94.4 +/- 12 mmHg (p < 0.01). Interdialytic weight gain decreased with salt restriction, 2.32 +/- 0.76 vs 1.78 +/- 0.49 kg (p < 0.001). The %R-BV was -7.25 +/- 2 (usual sodium intake) vs -5.91 +/- 2% (salt restriction), p < 0.01. Hypotensive episodes/session were 0.71 +/- 0.8 (usual sodium intake) vs 0.18 +/- 0.5 (salt restriction), p < 0.05. In conclusion, automatic measurement of sodium mass transfer is a practical tool to follow dietary salt ingestion in hemodialysis patients. It allows us accurate, individualised and continual dietary interventions. The use of exponential decrease sodium profiles improve dialysis tolerance without changes in sodium balance, interdialytic weight gain or arterial pressure. A reduction of three g in salt intake observed in this study was beneficial in interdialytic weight gain, dialysis tolerance and blood pressure control.